ACL Reconstruction

Anterior Cruciate Ligament

The anterior cruciate ligament is one of the major stabilizing ligaments in the knee. It is a strong rope like structure located in the centre of the knee running from the femur to the tibia. When this ligament tears unfortunately it doesn't heal and often leads to the feeling of instability in the knee.

ACL reconstruction is a commonly performed surgical procedure and with recent advances in arthroscopic surgery can now be performed with minimal incisions and low complication rates.


The ACL is the major stabilising ligaments in the knee. It prevents the tibia (Shin bone) moving abnormally on the femur (thigh bone). When this abnormal movement occurs it is referred to as instability and the patient is aware this abnormal movement.

Often other structures such as the meniscus, the articular cartilage (lining the joint) or other ligaments can also be damaged at the same time as a cruciate injury & these may need to be addressed at the time of surgery.

History of Injury

Most injuries are sports related involving a twisting injury to the knee. It can occurs with a sudden change of direction, a direct blow e.g., a tackle, landing awkwardly. Often there is a popping sound when the ligament ruptures. Swelling usually occurs within hours and there is often the feeling of the knee popping out of joint. It is rare to be able to continue playing sport with the initial injury.

Once the initial injury settles down the main symptom is instability or giving away of the knee. This usually occurs with running activities but can occur on simple walking or other activities of daily living.


The diagnoses can often be made on the history alone. Examination reveals instability of the knee, if adequately relaxed or not too painful.

An MRI (Magnetic Resonance Imaging) can be helpful if there is doubt as well as to look for damage to other structures within the knee. At times the final diagnoses can only be made under anaesthetic or with an arthroscopy.

ACL Surgery

You have injured your anterior cruciate ligament (ACL) and perhaps some other structures in the knee. Leaving this untreated in the young, active person often leads to ongoing episodes of instability. This makes participation in certain sporting and work activities difficult, and can also cause irreparable damage to the joint surfaces and the menisci (“cartilages”). In the longer term this can lead to progressive deterioration of the joint.

Surgery to treat the problem involves reconstructing the torn ligament with other tissue, usually either hamstring tendon or patellar tendon. Occasionally a transplanted tissue is required. There is not yet clear consensus about what is the best graft material, and both hamstring and patellar tendon reconstruction have excellent results in the majority of patients. Most surgeons agree that using your own tissue is generally preferable to someone else's, and we also know that pain in the area where the patellar tendon is removed (donor site) is usually greater than for the hamstrings. Dr Parker most commonly uses hamstrings, but will decide which is the most suitable graft in your case.

Before Surgery

Preoperative physiotherapy is helpful to better prepare the knee for surgery. The early aim is to regain range of motion, reduce swelling and achieve full weight bearing.

Certain medications, such as anti-inflammatory tablets and aspirin, need to be stopped prior to surgery. You should check with Dr Parker if any of the medications you are taking should be stopped. Also, please remember to bring any Xrays or scans with you. Ensure that you have no cuts or scratches on your skin, as this is an infection risk, and will usually result in surgery being deferred. Prior to going to the operating theatre you will meet the Anaesthetist who will discuss your anaesthetic history and any special risks. You will also see Dr Parker prior to surgery.

Day of Surgery

You will be admitted to hospital on the day of surgery.

After you are placed under anaesthetic you are given antibiotics, and the knee is examined to confirm instability of the ACL. If it is ruptured, reconstruction is carried out with the use of the arthroscope. This usually requires 3 small incisions. The incision for obtaining the hamstring graft is approximately 2 centimetres long just below the knee. Alternatively, if a patellar tendon graft is used, a 4 to 5cm incision is made along the front of the knee. Either of these incisions may produce a numb patch on the outside of the knee, which becomes smaller and less noticeable over time but can persist to a varying degree. This is because several small nerves in the skin are divided at the time of the skin incision. Accurately placed and sized tunnels are drilled in the femur and the tibia, and the graft inserted and fixed into position. Other problems such as meniscal tears and damage to the joint surface are fixed at the same time.

After Surgery

After surgery, your leg will be wrapped in a bulky dressing, and a drain is left in the knee. A brace is not used routinely. You will stay in hospital overnight. The following morning the drain and intravenous line will be removed, and the dressing made less bulky. The physiotherapist in hospital will assist you with some knee exercises and ensure safe mobility. Crutches are usually required for the first week or two, but can be discontinued once you are able to walk normally. The physiotherapist in hospital will commence your rehabilitation, which will then continue with your own physiotherapist after leaving hospital. It is important to protect the graft in the early months after surgery by avoiding “open chain” quadriceps exercises, and complying with the specific program you will be given.

Discharge from hospital is normally on the morning after surgery, once you are mobile with the crutches. Before you leave you will see Dr Parker, and will be given instructions and a referral for your physiotherapist and a prescription for painkillers.

The first review with Dr Parker is 2 weeks after the surgery. This is for review of the wounds and a discussion of the surgery. You will subsequently be checked at six weeks, three months, six months, one year and two years following the surgery. Your progress will be assessed, and special tests and questionnaires will be completed to better assess your result. The rehabilitation protocol given to your physiotherapist is very specific and should be followed strictly. Trying to progress too quickly may damage your knee.



Closed Kinetic Chain: exercise with the foot in contact with a surface, ie: leg press, squats, lunge


The muscle is shortening while it is contracting (‘positive con traction”)

Cybex Test

Strength testing machine that can measure force, work, and power of muscle groups.


The muscle is lengthening while it is contracting (‘negative contraction”)






Full Weight Bearing


Muscles in the back of the thigh


Tightening / contracting of a muscle without movement of the leg


Open Kinetic Chain: exercise when the lower leg is moving freely ie: leg extension


Exercises that enable a group of muscles to reach a maximum strength in as short a time as possible. It tries to bridge the gap between speed and strength training.


Lying on your stomach


Muscles on the front of the thigh


Range of Motion: amount of bending and straightening of the knee


Lying on your back


Rehabilitation requires a great deal of patient input. The best results are achieved by the patient who works well in rehabilitation and follows the protocol. Remember that if your knee hurts or swells, then your activity level has probably been too high.

Post-operative rehabilitation will be supervised by a physiotherapist and will involve activities such as exercise bike riding, swimming, proprioceptive exercises and muscle strengthening. Cycling can begin at 2 months, jogging can generally begin at around 3 months. The graft is strong enough to allow sport at around 6 months however other factors come into play such as confidence, fitness and adequate fitness and training.

Office work is usually possible two weeks after surgery and driving at this time is usually safe if you have good control of the leg. A job involving standing for prolonged periods is possible 5 to 6 weeks after surgery with heavy work at 3 months. Twisting or pivoting activities are introduced gradually after 6 months, and competitive sports after 9 months.

Professional sportsmen often return at 6 months but recreational athletes may take 10 -12 months depending on motivation and time put into rehabilitation.

The rehabilitation and overall success of the procedure can be affected by associated injuries to the knee such as damage to meniscus, articular cartilage or other ligaments.

The following is a more detailed rehabilitation protocol useful for patients and physiotherapists. It is a guide only and must be adjusted on an individual basis taking into account pain, other pathology, work and other social factors.

Acute (0 - 2 Weeks)


  1. Wound healing
  2. Reduce swelling
  3. Regain full extension
  4. Full weight bearing
  5. Wean off crutches
  6. Promote muscle control

Treatment Guidelines

  1. Pain and swelling reduction with ice, intermittent pressure pump, soft tissue massage and exercise
  2. Patella mobilisation
  3. Active range of motion knee exercises, calf and hamstring stretching, contraction (non weight bearing progressing to standing), muscle control and full weight bearing. Aim for full extension by 2 weeks. Full flexion will take longer and generally will come with gradual stretching. Care needs to be taken with hamstring co contraction as this may result in hamstring strains if too vigorous. Light hamstring loading continues into the next stage with progression of general rehabilitation. Resisted hamstring loading should be avoided for approximately 6 weeks
  4. Gait retraining encouraging extension at heel strike

Stage 2- Quadriceps Control (2-6 Weeks)


  1. Full active range of motion
  2. Normal gait with reasonable weight tolerance
  3. Minimal pain and effusion
  4. Develop muscular control for controlled pain free single leg lunge
  5. Avoid hamstring strain
  6. Develop early proprioceptive awareness

Treatment Guidelines

  1. Use active, passive and hands on techniques to promote full range of motion
  2. Progress closed chain exercises (quarter squats and single leg lunge) as pain allows. The emphasis is on pain free loading, VMO and gluteal activation
  3. Introduce gym based exercise equipment including leg press and stationary cycle
  4. Water based exercises can begin once the wound has healed, including treading water, gentle swimming avoiding breaststroke
  5. Begin proprioceptive exercises including single standing leg balance on the ground and mini tramp. This can progress by introducing body movement whilst standing on one leg
    Bilateral and single calf raises and stretching
  6. Avoid isolated loading of the hamstrings due to ease of tear. Hamstrings will be progressively loaded through closed chain and gym based activity

Stage 3- Hamstring/Quadriceps Strengthening (6-12 Weeks)

  1. Begin specific hamstring loading
  2. Increase total leg strength
  3. Promote good quadriceps control in lunge and hopping activity in preparation for running

Treatment Guidelines

  1. Focal hamstring loading begins and is progressed steadily throughout the next stages of rehabilitation
    • Active prone knee flexion which can be quickly progressed to include a light weight and gradually increasing weights
    • Bilateral bridging off a chair. This can be progressed by moving onto a single leg bridge and then single leg bridge with weight held across the abdomen
    • Single straight leg dead lift initially active with increasing difficulty by adding dumbbells
    • With respect to hamstring loading, they should never be pushed into pain and should be carefully progressed. Any subtle strain or tightness following exercises should be managed with a reduction in hamstring based exercises
  2. Gym based activity including leg presses, light squats and stationary bike which can be progressively increased in intensity as pain and control allow. It is important to monitor any effusions following exercise and if it is increasing then exercise should be toned down
  3. Once single leg lunge control is comparable to the other side hopping can be introduced. Hops can be made more difficult by including variations such as forward/back, side to side off a step and in a quadrant
  4. Running may begin towards the latter part of this stage. Prior to running certain criteria must be met:
    • No anterior knee pain
    • A pain free lunge and hop that is comparable to the other side
    • The knee must have no effusion
    • Before jogging start having brisk walks, ideally on a treadmill to monitor landing action and any effusion. This should be done for several weeks before jogging properly
  5. Increased proprioceptive manoeuvres with standing leg balance and progressive hopping based activity
  6. Expand calf routine to include eccentric loading

Stage Four-Sport Specific (3-6 Months)


  1. Improve leg strength
  2. Develop running endurance speed, change of direction
  3. Advanced proprioception
  4. Prepare for return to sport and recreational lifestyle

Treatment Guidelines

  1. Controlled sport specific activities should be included in the progression of running and gym loads. Increasing effusion post running that isn't easily managed with ice should result in a reduction in running loads
  2. Advanced proprioception to include controlled hopping and turning and balance correction
  3. Monitor potential problems associated with increasing loads
  4. No open chain resisted leg extension exercises unless authorised by Dr Parker

Stage Five-Return to Sport (6 Months Plus)


A safe return to sporting activities

Treatment Guidelines

  1. Full training for 1 month prior to active return to competitive sport
  2. Preparation for body contact sports. Begin with low intensity one on one contests and progress by increasing intensity and complexity in preparation for drills that one might be expected to do at training
  3. To improve running endurance leading up to a normal training session
  4. Full range, no effusion, good quadriceps control for lunge, hopping and hop and turn type activity. Circumference measures of thigh and calf to within 1 cm of other side.


Some of the potential complications of anterior cruciate ligament reconstruction include infection, blood clots, stiffness of the joint, pain, inadvertent injury to blood vessels and nerves, and recurrent instability, as well as anaesthetic complications. Failure of the graft may occur if excessive forces are placed upon it in the early post operative period Your co-operation with all instructions given by Dr Parker and your physiotherapist will help minimise these complications.

In particular, infection is a rare complication which requires prompt treatment. The major symptoms are fever, and increasing pain and swelling. Blood clots (deep venous thrombosis) are rare but can be serious. Calf pain or unexplained foot swelling may be caused by clots, and these or any other concerns should be reported to Dr Parker.

Injury Prevention Programs

Costs of ACL Reconstruction

Dr Parker’s charges and any associated gap not covered by Medicare and your health fund will be discussed with you when your surgery is arranged. Please feel free to discuss any aspect of this which is unclear to you, either with Dr Parker or his secretary.

If you have any questions concerning your surgery, its risks, benefits, likely outcome or complications please do not hesitate to contact Dr Parker.


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